path: root/eth/api.go

// Copyright 2015 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.

package eth

import (
    "bytes"
    "encoding/json"
    "errors"
    "fmt"
    "math/big"
    "sync"
    "time"

    "gopkg.in/fatih/set.v0"

    "github.com/ethereum/ethash"
    "github.com/ethereum/go-ethereum/accounts"
    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/common/compiler"
    "github.com/ethereum/go-ethereum/core"
    "github.com/ethereum/go-ethereum/core/state"
    "github.com/ethereum/go-ethereum/core/types"
    "github.com/ethereum/go-ethereum/core/vm"
    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/ethdb"
    "github.com/ethereum/go-ethereum/event"
    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/logger/glog"
    "github.com/ethereum/go-ethereum/rlp"
    rpc "github.com/ethereum/go-ethereum/rpc/v2"
)

const (
    defaultGasPrice = uint64(10000000000000)
    defaultGas = uint64(90000)
)

// PublicEthereumAPI provides an API to access Ethereum related information.
// It offers only methods that operate on public data that is freely available to anyone.
type PublicEthereumAPI struct {
    e   *Ethereum
    gpo *GasPriceOracle
}

// NewPublicEthereumAPI creates a new Etheruem protocol API.
func NewPublicEthereumAPI(e *Ethereum) *PublicEthereumAPI {
    return &PublicEthereumAPI{e, NewGasPriceOracle(e)}
}

// GasPrice returns a suggestion for a gas price.
func (s *PublicEthereumAPI) GasPrice() *big.Int {
    return s.gpo.SuggestPrice()
}

// GetCompilers returns the collection of available smart contract compilers
func (s *PublicEthereumAPI) GetCompilers() ([]string, error) {
    solc, err := s.e.Solc()
    if err != nil {
        return nil, err
    }

    if solc != nil {
        return []string{"Solidity"}, nil
    }

    return []string{}, nil
}

// CompileSolidity compiles the given solidity source
func (s *PublicEthereumAPI) CompileSolidity(source string) (map[string]*compiler.Contract, error) {
    solc, err := s.e.Solc()
    if err != nil {
        return nil, err
    }

    if solc == nil {
        return nil, errors.New("solc (solidity compiler) not found")
    }

    return solc.Compile(source)
}

// Etherbase is the address that mining rewards will be send to
func (s *PublicEthereumAPI) Etherbase() (common.Address, error) {
    return s.e.Etherbase()
}

// see Etherbase
func (s *PublicEthereumAPI) Coinbase() (common.Address, error) {
    return s.Etherbase()
}

// ProtocolVersion returns the current Ethereum protocol version this node supports
func (s *PublicEthereumAPI) ProtocolVersion() *rpc.HexNumber {
    return rpc.NewHexNumber(s.e.EthVersion())
}

// Hashrate returns the POW hashrate
func (s *PublicEthereumAPI) Hashrate() *rpc.HexNumber {
    return rpc.NewHexNumber(s.e.Miner().HashRate())
}

// Syncing returns false in case the node is currently not synching with the network. It can be up to date or has not
// yet received the latest block headers from its pears. In case it is synchronizing an object with 3 properties is
// returned:
// - startingBlock: block number this node started to synchronise from
// - currentBlock: block number this node is currently importing
// - highestBlock: block number of the highest block header this node has received from peers
func (s *PublicEthereumAPI) Syncing() (interface{}, error) {
    origin, current, height := s.e.Downloader().Progress()
    if current < height {
        return map[string]interface{}{
            "startingBlock": rpc.NewHexNumber(origin),
            "currentBlock":  rpc.NewHexNumber(current),
            "highestBlock":  rpc.NewHexNumber(height),
        }, nil
    }
    return false, nil
}

// PrivateMinerAPI provides private RPC methods to control the miner.
// These methods can be abused by external users and must be considered insecure for use by untrusted users.
type PrivateMinerAPI struct {
    e *Ethereum
}

// NewPrivateMinerAPI create a new RPC service which controls the miner of this node.
func NewPrivateMinerAPI(e *Ethereum) *PrivateMinerAPI {
    return &PrivateMinerAPI{e: e}
}

// Start the miner with the given number of threads
func (s *PrivateMinerAPI) Start(threads rpc.HexNumber) (bool, error) {
    s.e.StartAutoDAG()
    err := s.e.StartMining(threads.Int(), "")
    if err == nil {
        return true, nil
    }
    return false, err
}

// Stop the miner
func (s *PrivateMinerAPI) Stop() bool {
    s.e.StopMining()
    return true
}

// SetExtra sets the extra data string that is included when this miner mines a block.
func (s *PrivateMinerAPI) SetExtra(extra string) (bool, error) {
    if err := s.e.Miner().SetExtra([]byte(extra)); err != nil {
        return false, err
    }
    return true, nil
}

// SetGasPrice sets the minimum accepted gas price for the miner.
func (s *PrivateMinerAPI) SetGasPrice(gasPrice rpc.Number) bool {
    s.e.Miner().SetGasPrice(gasPrice.BigInt())
    return true
}

// SetEtherbase sets the etherbase of the miner
func (s *PrivateMinerAPI) SetEtherbase(etherbase common.Address) bool {
    s.e.SetEtherbase(etherbase)
    return true
}

// StartAutoDAG starts auto DAG generation. This will prevent the DAG generating on epoch change
// which will cause the node to stop mining during the generation process.
func (s *PrivateMinerAPI) StartAutoDAG() bool {
    s.e.StartAutoDAG()
    return true
}

// StopAutoDAG stops auto DAG generation
func (s *PrivateMinerAPI) StopAutoDAG() bool {
    s.e.StopAutoDAG()
    return true
}

// MakeDAG creates the new DAG for the given block number
func (s *PrivateMinerAPI) MakeDAG(blockNr rpc.BlockNumber) (bool, error) {
    if err := ethash.MakeDAG(uint64(blockNr.Int64()), ""); err != nil {
        return false, err
    }
    return true, nil
}

// PublicTxPoolAPI offers and API for the transaction pool. It only operates on data that is non confidential.
type PublicTxPoolAPI struct {
    e *Ethereum
}

// NewPublicTxPoolAPI creates a new tx pool service that gives information about the transaction pool.
func NewPublicTxPoolAPI(e *Ethereum) *PublicTxPoolAPI {
    return &PublicTxPoolAPI{e}
}

// Status returns the number of pending and queued transaction in the pool.
func (s *PublicTxPoolAPI) Status() map[string]*rpc.HexNumber {
    pending, queue := s.e.TxPool().Stats()
    return map[string]*rpc.HexNumber{
        "pending": rpc.NewHexNumber(pending),
        "queued":  rpc.NewHexNumber(queue),
    }
}

// PublicAccountAPI provides an API to access accounts managed by this node.
// It offers only methods that can retrieve accounts.
type PublicAccountAPI struct {
    am *accounts.Manager
}

// NewPublicAccountAPI creates a new PublicAccountAPI.
func NewPublicAccountAPI(am *accounts.Manager) *PublicAccountAPI {
    return &PublicAccountAPI{am: am}
}

// Accounts returns the collection of accounts this node manages
func (s *PublicAccountAPI) Accounts() ([]accounts.Account, error) {
    return s.am.Accounts()
}

// PrivateAccountAPI provides an API to access accounts managed by this node.
// It offers methods to create, (un)lock en list accounts.
type PrivateAccountAPI struct {
    am *accounts.Manager
}

// NewPrivateAccountAPI create a new PrivateAccountAPI.
func NewPrivateAccountAPI(am *accounts.Manager) *PrivateAccountAPI {
    return &PrivateAccountAPI{am}
}

// ListAccounts will return a list of addresses for accounts this node manages.
func (s *PrivateAccountAPI) ListAccounts() ([]common.Address, error) {
    accounts, err := s.am.Accounts()
    if err != nil {
        return nil, err
    }

    addresses := make([]common.Address, len(accounts))
    for i, acc := range accounts {
        addresses[i] = acc.Address
    }
    return addresses, nil
}

// NewAccount will create a new account and returns the address for the new account.
func (s *PrivateAccountAPI) NewAccount(password string) (common.Address, error) {
    acc, err := s.am.NewAccount(password)
    if err == nil {
        return acc.Address, nil
    }
    return common.Address{}, err
}

// UnlockAccount will unlock the account associated with the given address with the given password for duration seconds.
// It returns an indication if the action was successful.
func (s *PrivateAccountAPI) UnlockAccount(addr common.Address, password string, duration int) bool {
    if err := s.am.TimedUnlock(addr, password, time.Duration(duration)*time.Second); err != nil {
        glog.V(logger.Info).Infof("%v\n", err)
        return false
    }
    return true
}

// LockAccount will lock the account associated with the given address when it's unlocked.
func (s *PrivateAccountAPI) LockAccount(addr common.Address) bool {
    return s.am.Lock(addr) == nil
}

// PublicBlockChainAPI provides an API to access the Ethereum blockchain.
// It offers only methods that operate on public data that is freely available to anyone.
type PublicBlockChainAPI struct {
    bc       *core.BlockChain
    chainDb  ethdb.Database
    eventMux *event.TypeMux
    am       *accounts.Manager
}

// NewPublicBlockChainAPI creates a new Etheruem blockchain API.
func NewPublicBlockChainAPI(bc *core.BlockChain, chainDb ethdb.Database, eventMux *event.TypeMux, am *accounts.Manager) *PublicBlockChainAPI {
    return &PublicBlockChainAPI{bc: bc, chainDb: chainDb, eventMux: eventMux, am: am}
}

// BlockNumber returns the block number of the chain head.
func (s *PublicBlockChainAPI) BlockNumber() *big.Int {
    return s.bc.CurrentHeader().Number
}

// GetBalance returns the amount of wei for the given address in the state of the given block number.
// When block number equals rpc.LatestBlockNumber the current block is used.
func (s *PublicBlockChainAPI) GetBalance(address common.Address, blockNr rpc.BlockNumber) (*big.Int, error) {
    block := blockByNumber(s.bc, blockNr)
    if block == nil {
        return nil, nil
    }

    state, err := state.New(block.Root(), s.chainDb)
    if err != nil {
        return nil, err
    }
    return state.GetBalance(address), nil
}

// blockByNumber is a commonly used helper function which retrieves and returns the block for the given block number. It
// returns nil when no block could be found.
func blockByNumber(bc *core.BlockChain, blockNr rpc.BlockNumber) *types.Block {
    if blockNr == rpc.LatestBlockNumber {
        return bc.CurrentBlock()
    }

    return bc.GetBlockByNumber(uint64(blockNr))
}

// GetBlockByNumber returns the requested block. When blockNr is -1 the chain head is returned. When fullTx is true all
// transactions in the block are returned in full detail, otherwise only the transaction hash is returned.
func (s *PublicBlockChainAPI) GetBlockByNumber(blockNr rpc.BlockNumber, fullTx bool) (map[string]interface{}, error) {
    if block := blockByNumber(s.bc, blockNr); block != nil {
        return s.rpcOutputBlock(block, true, fullTx)
    }
    return nil, nil
}

// GetBlockByHash returns the requested block. When fullTx is true all transactions in the block are returned in full
// detail, otherwise only the transaction hash is returned.
func (s *PublicBlockChainAPI) GetBlockByHash(blockHash common.Hash, fullTx bool) (map[string]interface{}, error) {
    if block := s.bc.GetBlock(blockHash); block != nil {
        return s.rpcOutputBlock(block, true, fullTx)
    }
    return nil, nil
}

// GetUncleByBlockNumberAndIndex returns the uncle block for the given block hash and index. When fullTx is true
// all transactions in the block are returned in full detail, otherwise only the transaction hash is returned.
func (s *PublicBlockChainAPI) GetUncleByBlockNumberAndIndex(blockNr rpc.BlockNumber, index rpc.HexNumber) (map[string]interface{}, error) {
    if blockNr == rpc.PendingBlockNumber {
        return nil, nil
    }

    if block := blockByNumber(s.bc, blockNr); block != nil {
        uncles := block.Uncles()
        if index.Int() < 0 || index.Int() >= len(uncles) {
            glog.V(logger.Debug).Infof("uncle block on index %d not found for block #%d", index.Int(), blockNr)
            return nil, nil
        }
        block = types.NewBlockWithHeader(uncles[index.Int()])
        return s.rpcOutputBlock(block, false, false)
    }
    return nil, nil
}

// GetUncleByBlockHashAndIndex returns the uncle block for the given block hash and index. When fullTx is true
// all transactions in the block are returned in full detail, otherwise only the transaction hash is returned.
func (s *PublicBlockChainAPI) GetUncleByBlockHashAndIndex(blockHash common.Hash, index rpc.HexNumber) (map[string]interface{}, error) {
    if block := s.bc.GetBlock(blockHash); block != nil {
        uncles := block.Uncles()
        if index.Int() < 0 || index.Int() >= len(uncles) {
            glog.V(logger.Debug).Infof("uncle block on index %d not found for block %s", index.Int(), blockHash.Hex())
            return nil, nil
        }
        block = types.NewBlockWithHeader(uncles[index.Int()])
        return s.rpcOutputBlock(block, false, false)
    }
    return nil, nil
}

// GetUncleCountByBlockNumber returns number of uncles in the block for the given block number
func (s *PublicBlockChainAPI) GetUncleCountByBlockNumber(blockNr rpc.BlockNumber) *rpc.HexNumber {
    if blockNr == rpc.PendingBlockNumber {
        return rpc.NewHexNumber(0)
    }

    if block := blockByNumber(s.bc, blockNr); block != nil {
        return rpc.NewHexNumber(len(block.Uncles()))
    }
    return nil
}

// GetUncleCountByBlockHash returns number of uncles in the block for the given block hash
func (s *PublicBlockChainAPI) GetUncleCountByBlockHash(blockHash common.Hash) *rpc.HexNumber {
    if block := s.bc.GetBlock(blockHash); block != nil {
        return rpc.NewHexNumber(len(block.Uncles()))
    }
    return nil
}

// NewBlocksArgs allows the user to specify if the returned block should include transactions and in which format.
type NewBlocksArgs struct {
    IncludeTransactions bool `json:"includeTransactions"`
    TransactionDetails  bool `json:"transactionDetails"`
}

// NewBlocks triggers a new block event each time a block is appended to the chain. It accepts an argument which allows
// the caller to specify whether the output should contain transactions and in what format.
func (s *PublicBlockChainAPI) NewBlocks(args NewBlocksArgs) (rpc.Subscription, error) {
    sub := s.eventMux.Subscribe(core.ChainEvent{})

    output := func(rawBlock interface{}) interface{} {
        if event, ok := rawBlock.(core.ChainEvent); ok {
            notification, err := s.rpcOutputBlock(event.Block, args.IncludeTransactions, args.TransactionDetails)
            if err == nil {
                return notification
            }
        }
        return rawBlock
    }

    return rpc.NewSubscriptionWithOutputFormat(sub, output), nil
}

// GetCode returns the code stored at the given address in the state for the given block number.
func (s *PublicBlockChainAPI) GetCode(address common.Address, blockNr rpc.BlockNumber) (string, error) {
    return s.GetData(address, blockNr)
}

// GetData returns the data stored at the given address in the state for the given block number.
func (s *PublicBlockChainAPI) GetData(address common.Address, blockNr rpc.BlockNumber) (string, error) {
    if block := blockByNumber(s.bc, blockNr); block != nil {
        state, err := state.New(block.Root(), s.chainDb)
        if err != nil {
            return "", err
        }
        res := state.GetCode(address)
        if len(res) == 0 { // backwards compatibility
            return "0x", nil
        }
        return common.ToHex(res), nil
    }

    return "0x", nil
}

// GetStorageAt returns the storage from the state at the given address, key and block number.
func (s *PublicBlockChainAPI) GetStorageAt(address common.Address, key string, blockNr rpc.BlockNumber) (string, error) {
    if block := blockByNumber(s.bc, blockNr); block != nil {
        state, err := state.New(block.Root(), s.chainDb)
        if err != nil {
            return "", err
        }

        return state.GetState(address, common.HexToHash(key)).Hex(), nil
    }

    return "0x", nil
}

// callmsg is the message type used for call transations.
type callmsg struct {
    from          *state.StateObject
    to            *common.Address
    gas, gasPrice *big.Int
    value         *big.Int
    data          []byte
}

// accessor boilerplate to implement core.Message
func (m callmsg) From() (common.Address, error) { return m.from.Address(), nil }
func (m callmsg) Nonce() uint64 { return m.from.Nonce() }
func (m callmsg) To() *common.Address { return m.to }
func (m callmsg) GasPrice() *big.Int { return m.gasPrice }
func (m callmsg) Gas() *big.Int { return m.gas }
func (m callmsg) Value() *big.Int { return m.value }
func (m callmsg) Data() []byte { return m.data }

type CallArgs struct {
    From     common.Address `json:"from"`
    To       common.Address `json:"to"`
    Gas      rpc.HexNumber  `json:"gas"`
    GasPrice rpc.HexNumber  `json:"gasPrice"`
    Value    rpc.HexNumber  `json:"value"`
    Data     string         `json:"data"`
}

func (s *PublicBlockChainAPI) doCall(args CallArgs, blockNr rpc.BlockNumber) (string, *big.Int, error) {
    if block := blockByNumber(s.bc, blockNr); block != nil {
        stateDb, err := state.New(block.Root(), s.chainDb)
        if err != nil {
            return "0x", nil, err
        }

        stateDb = stateDb.Copy()
        var from *state.StateObject
        if args.From == (common.Address{}) {
            accounts, err := s.am.Accounts()
            if err != nil || len(accounts) == 0 {
                from = stateDb.GetOrNewStateObject(common.Address{})
            } else {
                from = stateDb.GetOrNewStateObject(accounts[0].Address)
            }
        } else {
            from = stateDb.GetOrNewStateObject(args.From)
        }

        from.SetBalance(common.MaxBig)

        msg := callmsg{
            from:     from,
            to:       &args.To,
            gas:      args.Gas.BigInt(),
            gasPrice: args.GasPrice.BigInt(),
            value:    args.Value.BigInt(),
            data:     common.FromHex(args.Data),
        }

        if msg.gas.Cmp(common.Big0) == 0 {
            msg.gas = big.NewInt(50000000)
        }

        if msg.gasPrice.Cmp(common.Big0) == 0 {
            msg.gasPrice = new(big.Int).Mul(big.NewInt(50), common.Shannon)
        }

        header := s.bc.CurrentBlock().Header()
        vmenv := core.NewEnv(stateDb, s.bc, msg, header)
        gp := new(core.GasPool).AddGas(common.MaxBig)
        res, gas, err := core.ApplyMessage(vmenv, msg, gp)
        if len(res) == 0 { // backwards compatability
            return "0x", gas, err
        }
        return common.ToHex(res), gas, err
    }

    return "0x", common.Big0, nil
}

// Call executes the given transaction on the state for the given block number.
// It doesn't make and changes in the state/blockchain and is usefull to execute and retrieve values.
func (s *PublicBlockChainAPI) Call(args CallArgs, blockNr rpc.BlockNumber) (string, error) {
    result, _, err := s.doCall(args, blockNr)
    return result, err
}

// EstimateGas returns an estimate of the amount of gas needed to execute the given transaction.
func (s *PublicBlockChainAPI) EstimateGas(args CallArgs) (*rpc.HexNumber, error) {
    _, gas, err := s.doCall(args, rpc.LatestBlockNumber)
    return rpc.NewHexNumber(gas), err
}

// rpcOutputBlock converts the given block to the RPC output which depends on fullTx. If inclTx is true transactions are
// returned. When fullTx is true the returned block contains full transaction details, otherwise it will only contain
// transaction hashes.
func (s *PublicBlockChainAPI) rpcOutputBlock(b *types.Block, inclTx bool, fullTx bool) (map[string]interface{}, error) {
    fields := map[string]interface{}{
        "number":           rpc.NewHexNumber(b.Number()),
        "hash":             b.Hash(),
        "parentHash":       b.ParentHash(),
        "nonce":            b.Header().Nonce,
        "sha3Uncles":       b.UncleHash(),
        "logsBloom":        b.Bloom(),
        "stateRoot":        b.Root(),
        "miner":            b.Coinbase(),
        "difficulty":       rpc.NewHexNumber(b.Difficulty()),
        "totalDifficulty":  rpc.NewHexNumber(s.bc.GetTd(b.Hash())),
        "extraData":        fmt.Sprintf("0x%x", b.Extra()),
        "size":             rpc.NewHexNumber(b.Size().Int64()),
        "gasLimit":         rpc.NewHexNumber(b.GasLimit()),
        "gasUsed":          rpc.NewHexNumber(b.GasUsed()),
        "timestamp":        rpc.NewHexNumber(b.Time()),
        "transactionsRoot": b.TxHash(),
        "receiptRoot":      b.ReceiptHash(),
    }

    if inclTx {
        formatTx := func(tx *types.Transaction) (interface{}, error) {
            return tx.Hash(), nil
        }

        if fullTx {
            formatTx = func(tx *types.Transaction) (interface{}, error) {
                return newRPCTransaction(b, tx.Hash())
            }
        }

        txs := b.Transactions()
        transactions := make([]interface{}, len(txs))
        var err error
        for i, tx := range b.Transactions() {
            if transactions[i], err = formatTx(tx); err != nil {
                return nil, err
            }
        }
        fields["transactions"] = transactions
    }

    uncles := b.Uncles()
    uncleHashes := make([]common.Hash, len(uncles))
    for i, uncle := range uncles {
        uncleHashes[i] = uncle.Hash()
    }
    fields["uncles"] = uncleHashes

    return fields, nil
}

// RPCTransaction represents a transaction that will serialize to the RPC representation of a transaction
type RPCTransaction struct {
    BlockHash        common.Hash     `json:"blockHash"`
    BlockNumber      *rpc.HexNumber  `json:"blockNumber"`
    From             common.Address  `json:"from"`
    Gas              *rpc.HexNumber  `json:"gas"`
    GasPrice         *rpc.HexNumber  `json:"gasPrice"`
    Hash             common.Hash     `json:"hash"`
    Input            string          `json:"input"`
    Nonce            *rpc.HexNumber  `json:"nonce"`
    To               *common.Address `json:"to"`
    TransactionIndex *rpc.HexNumber  `json:"transactionIndex"`
    Value            *rpc.HexNumber  `json:"value"`
}

// newRPCPendingTransaction returns a pending transaction that will serialize to the RPC representation
func newRPCPendingTransaction(tx *types.Transaction) *RPCTransaction {
    from, _ := tx.From()

    return &RPCTransaction{
        From:     from,
        Gas:      rpc.NewHexNumber(tx.Gas()),
        GasPrice: rpc.NewHexNumber(tx.GasPrice()),
        Hash:     tx.Hash(),
        Input:    fmt.Sprintf("0x%x", tx.Data()),
        Nonce:    rpc.NewHexNumber(tx.Nonce()),
        To:       tx.To(),
        Value:    rpc.NewHexNumber(tx.Value()),
    }
}

// newRPCTransaction returns a transaction that will serialize to the RPC representation.
func newRPCTransactionFromBlockIndex(b *types.Block, txIndex int) (*RPCTransaction, error) {
    if txIndex >= 0 && txIndex < len(b.Transactions()) {
        tx := b.Transactions()[txIndex]
        from, err := tx.From()
        if err != nil {
            return nil, err
        }

        return &RPCTransaction{
            BlockHash:        b.Hash(),
            BlockNumber:      rpc.NewHexNumber(b.Number()),
            From:             from,
            Gas:              rpc.NewHexNumber(tx.Gas()),
            GasPrice:         rpc.NewHexNumber(tx.GasPrice()),
            Hash:             tx.Hash(),
            Input:            fmt.Sprintf("0x%x", tx.Data()),
            Nonce:            rpc.NewHexNumber(tx.Nonce()),
            To:               tx.To(),
            TransactionIndex: rpc.NewHexNumber(txIndex),
            Value:            rpc.NewHexNumber(tx.Value()),
        }, nil
    }

    return nil, nil
}

// newRPCTransaction returns a transaction that will serialize to the RPC representation.
func newRPCTransaction(b *types.Block, txHash common.Hash) (*RPCTransaction, error) {
    for idx, tx := range b.Transactions() {
        if tx.Hash() == txHash {
            return newRPCTransactionFromBlockIndex(b, idx)
        }
    }

    return nil, nil
}

// PublicTransactionPoolAPI exposes methods for the RPC interface
type PublicTransactionPoolAPI struct {
    eventMux *event.TypeMux
    chainDb  ethdb.Database
    bc       *core.BlockChain
    am       *accounts.Manager
    txPool   *core.TxPool
    txMu     sync.Mutex
}

// NewPublicTransactionPoolAPI creates a new RPC service with methods specific for the transaction pool.
func NewPublicTransactionPoolAPI(txPool *core.TxPool, chainDb ethdb.Database, eventMux *event.TypeMux, bc *core.BlockChain, am *accounts.Manager) *PublicTransactionPoolAPI {
    return &PublicTransactionPoolAPI{
        eventMux: eventMux,
        chainDb:  chainDb,
        bc:       bc,
        am:       am,
        txPool:   txPool,
    }
}

func getTransaction(chainDb ethdb.Database, txPool *core.TxPool, txHash common.Hash) (*types.Transaction, bool, error) {
    txData, err := chainDb.Get(txHash.Bytes())
    isPending := false
    tx := new(types.Transaction)

    if err == nil && len(txData) > 0 {
        if err := rlp.DecodeBytes(txData, tx); err != nil {
            return nil, isPending, err
        }
    } else {
        // pending transaction?
        tx = txPool.GetTransaction(txHash)
        isPending = true
    }

    return tx, isPending, nil
}

// GetBlockTransactionCountByNumber returns the number of transactions in the block with the given block number.
func (s *PublicTransactionPoolAPI) GetBlockTransactionCountByNumber(blockNr rpc.BlockNumber) *rpc.HexNumber {
    if blockNr == rpc.PendingBlockNumber {
        return rpc.NewHexNumber(0)
    }

    if block := blockByNumber(s.bc, blockNr); block != nil {
        return rpc.NewHexNumber(len(block.Transactions()))
    }

    return nil
}

// GetBlockTransactionCountByHash returns the number of transactions in the block with the given hash.
func (s *PublicTransactionPoolAPI) GetBlockTransactionCountByHash(blockHash common.Hash) *rpc.HexNumber {
    if block := s.bc.GetBlock(blockHash); block != nil {
        return rpc.NewHexNumber(len(block.Transactions()))
    }
    return nil
}

// GetTransactionByBlockNumberAndIndex returns the transaction for the given block number and index.
func (s *PublicTransactionPoolAPI) GetTransactionByBlockNumberAndIndex(blockNr rpc.BlockNumber, index rpc.HexNumber) (*RPCTransaction, error) {
    if block := blockByNumber(s.bc, blockNr); block != nil {
        return newRPCTransactionFromBlockIndex(block, index.Int())
    }
    return nil, nil
}

// GetTransactionByBlockHashAndIndex returns the transaction for the given block hash and index.
func (s *PublicTransactionPoolAPI) GetTransactionByBlockHashAndIndex(blockHash common.Hash, index rpc.HexNumber) (*RPCTransaction, error) {
    if block := s.bc.GetBlock(blockHash); block != nil {
        return newRPCTransactionFromBlockIndex(block, index.Int())
    }
    return nil, nil
}

// GetTransactionCount returns the number of transactions the given address has sent for the given block number
func (s *PublicTransactionPoolAPI) GetTransactionCount(address common.Address, blockNr rpc.BlockNumber) (*rpc.HexNumber, error) {
    block := blockByNumber(s.bc, blockNr)
    if block == nil {
        return nil, nil
    }

    state, err := state.New(block.Root(), s.chainDb)
    if err != nil {
        return nil, err
    }
    return rpc.NewHexNumber(state.GetNonce(address)), nil
}

// getTransactionBlockData fetches the meta data for the given transaction from the chain database. This is useful to
// retrieve block information for a hash. It returns the block hash, block index and transaction index.
func getTransactionBlockData(chainDb ethdb.Database, txHash common.Hash) (common.Hash, uint64, uint64, error) {
    var txBlock struct {
        BlockHash  common.Hash
        BlockIndex uint64
        Index      uint64
    }

    blockData, err := chainDb.Get(append(txHash.Bytes(), 0x0001))
    if err != nil {
        return common.Hash{}, uint64(0), uint64(0), err
    }

    reader := bytes.NewReader(blockData)
    if err = rlp.Decode(reader, &txBlock); err != nil {
        return common.Hash{}, uint64(0), uint64(0), err
    }

    return txBlock.BlockHash, txBlock.BlockIndex, txBlock.Index, nil
}

// GetTransactionByHash returns the transaction for the given hash
func (s *PublicTransactionPoolAPI) GetTransactionByHash(txHash common.Hash) (*RPCTransaction, error) {
    var tx *types.Transaction
    var isPending bool
    var err error

    if tx, isPending, err = getTransaction(s.chainDb, s.txPool, txHash); err != nil {
        glog.V(logger.Debug).Infof("%v\n", err)
        return nil, nil
    } else if tx == nil {
        return nil, nil
    }

    if isPending {
        return newRPCPendingTransaction(tx), nil
    }

    blockHash, _, _, err := getTransactionBlockData(s.chainDb, txHash)
    if err != nil {
        glog.V(logger.Debug).Infof("%v\n", err)
        return nil, nil
    }

    if block := s.bc.GetBlock(blockHash); block != nil {
        return newRPCTransaction(block, txHash)
    }

    return nil, nil
}

// GetTransactionReceipt returns the transaction receipt for the given transaction hash.
func (s *PublicTransactionPoolAPI) GetTransactionReceipt(txHash common.Hash) (map[string]interface{}, error) {
    receipt := core.GetReceipt(s.chainDb, txHash)
    if receipt == nil {
        glog.V(logger.Debug).Infof("receipt not found for transaction %s", txHash.Hex())
        return nil, nil
    }

    tx, _, err := getTransaction(s.chainDb, s.txPool, txHash)
    if err != nil {
        glog.V(logger.Debug).Infof("%v\n", err)
        return nil, nil
    }

    txBlock, blockIndex, index, err := getTransactionBlockData(s.chainDb, txHash)
    if err != nil {
        glog.V(logger.Debug).Infof("%v\n", err)
        return nil, nil
    }

    from, err := tx.From()
    if err != nil {
        glog.V(logger.Debug).Infof("%v\n", err)
        return nil, nil
    }

    fields := map[string]interface{}{
        "blockHash":         txBlock,
        "blockNumber":       rpc.NewHexNumber(blockIndex),
        "transactionHash":   txHash,
        "transactionIndex":  rpc.NewHexNumber(index),
        "from":              from,
        "to":                tx.To(),
        "gasUsed":           rpc.NewHexNumber(receipt.GasUsed),
        "cumulativeGasUsed": rpc.NewHexNumber(receipt.CumulativeGasUsed),
        "contractAddress":   nil,
        "logs":              receipt.Logs,
    }

    if receipt.Logs == nil {
        fields["logs"] = []vm.Logs{}
    }

    // If the ContractAddress is 20 0x0 bytes, assume it is not a contract creation
    if bytes.Compare(receipt.ContractAddress.Bytes(), bytes.Repeat([]byte{0}, 20)) != 0 {
        fields["contractAddress"] = receipt.ContractAddress
    }

    return fields, nil
}

// sign is a helper function that signs a transaction with the private key of the given address.
func (s *PublicTransactionPoolAPI) sign(address common.Address, tx *types.Transaction) (*types.Transaction, error) {
    acc := accounts.Account{address}
    signature, err := s.am.Sign(acc, tx.SigHash().Bytes())
    if err != nil {
        return nil, err
    }
    return tx.WithSignature(signature)
}

type SendTxArgs struct {
    From     common.Address `json:"from"`
    To       common.Address `json:"to"`
    Gas      *rpc.HexNumber `json:"gas"`
    GasPrice *rpc.HexNumber `json:"gasPrice"`
    Value    *rpc.HexNumber `json:"value"`
    Data     string         `json:"data"`
    Nonce    *rpc.HexNumber `json:"nonce"`
}

// SendTransaction will create a transaction for the given transaction argument, sign it and submit it to the
// transaction pool.
func (s *PublicTransactionPoolAPI) SendTransaction(args SendTxArgs) (common.Hash, error) {
    if args.Gas == nil {
        args.Gas = rpc.NewHexNumber(defaultGas)
    }
    if args.GasPrice == nil {
        args.GasPrice = rpc.NewHexNumber(defaultGasPrice)
    }
    if args.Value == nil {
        args.Value = rpc.NewHexNumber(0)
    }

    s.txMu.Lock()
    defer s.txMu.Unlock()

    if args.Nonce == nil {
        args.Nonce = rpc.NewHexNumber(s.txPool.State().GetNonce(args.From))
    }

    var tx *types.Transaction
    contractCreation := (args.To == common.Address{})

    if contractCreation {
        tx = types.NewContractCreation(args.Nonce.Uint64(), args.Value.BigInt(), args.Gas.BigInt(), args.GasPrice.BigInt(), common.FromHex(args.Data))
    } else {
        tx = types.NewTransaction(args.Nonce.Uint64(), args.To, args.Value.BigInt(), args.Gas.BigInt(), args.GasPrice.BigInt(), common.FromHex(args.Data))
    }

    signedTx, err := s.sign(args.From, tx)
    if err != nil {
        return common.Hash{}, err
    }

    if err := s.txPool.Add(signedTx); err != nil {
        return common.Hash{}, nil
    }

    if contractCreation {
        addr := crypto.CreateAddress(args.From, args.Nonce.Uint64())
        glog.V(logger.Info).Infof("Tx(%s) created: %s\n", signedTx.Hash().Hex(), addr.Hex())
    } else {
        glog.V(logger.Info).Infof("Tx(%s) to: %s\n", signedTx.Hash().Hex(), tx.To().Hex())
    }

    return signedTx.Hash(), nil
}

// SendRawTransaction will add the signed transaction to the transaction pool.
// The sender is responsible for signing the transaction and using the correct nonce.
func (s *PublicTransactionPoolAPI) SendRawTransaction(encodedTx string) (string, error) {
    tx := new(types.Transaction)
    if err := rlp.DecodeBytes(common.FromHex(encodedTx), tx); err != nil {
        return "", err
    }

    if err := s.txPool.Add(tx); err != nil {
        return "", err
    }

    if tx.To() == nil {
        from, err := tx.From()
        if err != nil {
            return "", err
        }
        addr := crypto.CreateAddress(from, tx.Nonce())
        glog.V(logger.Info).Infof("Tx(%x) created: %x\n", tx.Hash(), addr)
    } else {
        glog.V(logger.Info).Infof("Tx(%x) to: %x\n", tx.Hash(), tx.To())
    }

    return tx.Hash().Hex(), nil
}

// Sign will sign the given data string with the given address. The account corresponding with the address needs to
// be unlocked.
func (s *PublicTransactionPoolAPI) Sign(address common.Address, data string) (string, error) {
    signature, error := s.am.Sign(accounts.Account{Address: address}, common.HexToHash(data).Bytes())
    return common.ToHex(signature), error
}

type SignTransactionArgs struct {
    From        common.Address
    To          common.Address
    Nonce       *rpc.HexNumber
    Value       *rpc.HexNumber
    Gas         *rpc.HexNumber
    GasPrice    *rpc.HexNumber
    Data        string

    BlockNumber int64
}

// Tx is a helper object for argument and return values
type Tx struct {
    tx       *types.Transaction

    To       *common.Address `json:"to"`
    From     common.Address  `json:"from"`
    Nonce    *rpc.HexNumber  `json:"nonce"`
    Value    *rpc.HexNumber  `json:"value"`
    Data     string          `json:"data"`
    GasLimit *rpc.HexNumber  `json:"gas"`
    GasPrice *rpc.HexNumber  `json:"gasPrice"`
    Hash     common.Hash     `json:"hash"`
}

func (tx *Tx) UnmarshalJSON(b []byte) (err error) {
    req := struct {
        To       common.Address `json:"to"`
        From     common.Address `json:"from"`
        Nonce    *rpc.HexNumber `json:"nonce"`
        Value    *rpc.HexNumber `json:"value"`
        Data     string         `json:"data"`
        GasLimit *rpc.HexNumber `json:"gas"`
        GasPrice *rpc.HexNumber `json:"gasPrice"`
        Hash     common.Hash    `json:"hash"`
    }{}

    if err := json.Unmarshal(b, &req); err != nil {
        return err
    }

    contractCreation := (req.To == (common.Address{}))

    tx.To = &req.To
    tx.From = req.From
    tx.Nonce = req.Nonce
    tx.Value = req.Value
    tx.Data = req.Data
    tx.GasLimit = req.GasLimit
    tx.GasPrice = req.GasPrice
    tx.Hash = req.Hash

    data := common.Hex2Bytes(tx.Data)

    if tx.Nonce == nil {
        return fmt.Errorf("need nonce")
    }
    if tx.Value == nil {
        tx.Value = rpc.NewHexNumber(0)
    }
    if tx.GasLimit == nil {
        tx.GasLimit = rpc.NewHexNumber(0)
    }
    if tx.GasPrice == nil {
        tx.GasPrice = rpc.NewHexNumber(defaultGasPrice)
    }

    if contractCreation {
        tx.tx = types.NewContractCreation(tx.Nonce.Uint64(), tx.Value.BigInt(), tx.GasLimit.BigInt(), tx.GasPrice.BigInt(), data)
    } else {
        if tx.To == nil {
            return fmt.Errorf("need to address")
        }
        tx.tx = types.NewTransaction(tx.Nonce.Uint64(), *tx.To, tx.Value.BigInt(), tx.GasLimit.BigInt(), tx.GasPrice.BigInt(), data)
    }

    return nil
}

type SignTransactionResult struct {
    Raw string `json:"raw"`
    Tx  *Tx    `json:"tx"`
}

func newTx(t *types.Transaction) *Tx {
    from, _ := t.From()
    return &Tx{
        tx:       t,
        To:       t.To(),
        From:     from,
        Value:    rpc.NewHexNumber(t.Value()),
        Nonce:    rpc.NewHexNumber(t.Nonce()),
        Data:     "0x" + common.Bytes2Hex(t.Data()),
        GasLimit: rpc.NewHexNumber(t.Gas()),
        GasPrice: rpc.NewHexNumber(t.GasPrice()),
        Hash:     t.Hash(),
    }
}

// SignTransaction will sign the given transaction with the from account.
// The node needs to have the private key of the account corresponding with
// the given from address and it needs to be unlocked.
func (s *PublicTransactionPoolAPI) SignTransaction(args *SignTransactionArgs) (*SignTransactionResult, error) {
    if args.Gas == nil {
        args.Gas = rpc.NewHexNumber(defaultGas)
    }
    if args.GasPrice == nil {
        args.GasPrice = rpc.NewHexNumber(defaultGasPrice)
    }
    if args.Value == nil {
        args.Value = rpc.NewHexNumber(0)
    }

    s.txMu.Lock()
    defer s.txMu.Unlock()

    if args.Nonce == nil {
        args.Nonce = rpc.NewHexNumber(s.txPool.State().GetNonce(args.From))
    }

    var tx *types.Transaction
    contractCreation := (args.To == common.Address{})

    if contractCreation {
        tx = types.NewContractCreation(args.Nonce.Uint64(), args.Value.BigInt(), args.Gas.BigInt(), args.GasPrice.BigInt(), common.FromHex(args.Data))
    } else {
        tx = types.NewTransaction(args.Nonce.Uint64(), args.To, args.Value.BigInt(), args.Gas.BigInt(), args.GasPrice.BigInt(), common.FromHex(args.Data))
    }

    signedTx, err := s.sign(args.From, tx)
    if err != nil {
        return nil, err
    }

    data, err := rlp.EncodeToBytes(signedTx)
    if err != nil {
        return nil, err
    }

    return &SignTransactionResult{"0x" + common.Bytes2Hex(data), newTx(tx)}, nil
}

// PendingTransactions returns the transactions that are in the transaction pool and have a from address that is one of
// the accounts this node manages.
func (s *PublicTransactionPoolAPI) PendingTransactions() ([]*RPCTransaction, error) {
    accounts, err := s.am.Accounts()
    if err != nil {
        return nil, err
    }

    accountSet := set.New()
    for _, account := range accounts {
        accountSet.Add(account.Address)
    }

    pending := s.txPool.GetTransactions()
    transactions := make([]*RPCTransaction, 0)
    for _, tx := range pending {
        if from, _ := tx.From(); accountSet.Has(from) {
            transactions = append(transactions, newRPCPendingTransaction(tx))
        }
    }

    return transactions, nil
}

// NewPendingTransaction creates a subscription that is triggered each time a transaction enters the transaction pool
// and is send from one of the transactions this nodes manages.
func (s *PublicTransactionPoolAPI) NewPendingTransactions() (rpc.Subscription, error) {
    sub := s.eventMux.Subscribe(core.TxPreEvent{})

    accounts, err := s.am.Accounts()
    if err != nil {
        return rpc.Subscription{}, err
    }
    accountSet := set.New()
    for _, account := range accounts {
        accountSet.Add(account.Address)
    }
    accountSetLastUpdates := time.Now()

    output := func(transaction interface{}) interface{} {
        if time.Since(accountSetLastUpdates) > (time.Duration(2) * time.Second) {
            if accounts, err = s.am.Accounts(); err != nil {
                accountSet.Clear()
                for _, account := range accounts {
                    accountSet.Add(account.Address)
                }
                accountSetLastUpdates = time.Now()
            }
        }

        tx := transaction.(core.TxPreEvent)
        if from, err := tx.Tx.From(); err == nil {
            if accountSet.Has(from) {
                return tx.Tx.Hash()
            }
        }
        return nil
    }

    return rpc.NewSubscriptionWithOutputFormat(sub, output), nil
}

// Resend accepts an existing transaction and a new gas price and limit. It will remove the given transaction from the
// pool and reinsert it with the new gas price and limit.
func (s *PublicTransactionPoolAPI) Resend(tx *Tx, gasPrice, gasLimit *rpc.HexNumber) (common.Hash, error) {

    pending := s.txPool.GetTransactions()
    for _, p := range pending {
        if pFrom, err := p.From(); err == nil && pFrom == tx.From && p.SigHash() == tx.tx.SigHash() {
            if gasPrice == nil {
                gasPrice = rpc.NewHexNumber(tx.tx.GasPrice())
            }
            if gasLimit == nil {
                gasLimit = rpc.NewHexNumber(tx.tx.Gas())
            }

            var newTx *types.Transaction
            contractCreation := (*tx.tx.To() == common.Address{})
            if contractCreation {
                newTx = types.NewContractCreation(tx.tx.Nonce(), tx.tx.Value(), gasPrice.BigInt(), gasLimit.BigInt(), tx.tx.Data())
            } else {
                newTx = types.NewTransaction(tx.tx.Nonce(), *tx.tx.To(), tx.tx.Value(), gasPrice.BigInt(), gasLimit.BigInt(), tx.tx.Data())
            }

            signedTx, err := s.sign(tx.From, newTx)
            if err != nil {
                return common.Hash{}, err
            }

            s.txPool.RemoveTx(tx.Hash)
            if err = s.txPool.Add(signedTx); err != nil {
                return common.Hash{}, err
            }

            return signedTx.Hash(), nil
        }
    }

    return common.Hash{}, fmt.Errorf("Transaction %#x not found", tx.Hash)
}